Robert Hogan

Tooth‐Brushing Epilepsy: A Report of a Case with Structural and Functional Imaging and Electrophysiology Demonstrating a Right Frontal Focus

Summary: Patients with reflex epilepsies may provide insights into cerebral pathophysiology. We report a patient with an unusual form of reflex epilepsy in whom seizures are induced by tooth brushing. Magnetic resonance imaging (MRI) demonstrated a right posterior frontal low‐grade tumor predominantly involving the precentral gyrus. Video‐telemetry demonstrated right‐sided epileptiform activity during a typical induced complex partial seizure. An ictal single photon emission computed tomography (SPECT) scan showed an area of hyperfusion that corresponded to the MRI lesion on coregistration with a surface‐matching technique. A subsequent coregistered interictal SPECT scan demonstrated hypoperfusion in the same region. Ours is the first report to demonstrate a structural focus in this unusual form of reflex epilepsy. Possible mechanisms to explain the induction of the seizures are discussed.

Hippocampal deformation mapping in MRI negative PET positive temporal lobe epilepsy

Objectives: To compare hippocampal surface structure, using large deformation high dimensional mapping (HDM-LD), in subjects with temporal lobe epilepsy (TLE) with (HS+ve) and without (HS−ve) hippocampal sclerosis. Methods: The study included 30 HS−ve subjects matched with 30 HS+ve subjects from the previously reported epilepsy patient cohort. To control for normal right–left asymmetries of hippocampal surface structure, subjects were regrouped based on laterality of onset of epileptic seizures and presence of HS. Gender ratio, age, duration of epilepsy and seizure frequency were calculated for each of the four groups. Final HDM-LD surface maps of the right and left TLE groups were compared to define differences in subregional hippocampal involvement within the groups. Results: There were no significant differences in comparisons of the left TLE (left HS−ve compared with HS+ve) or right TLE (right HS−ve compared with HS+ve) groups with respect to age, duration of epilepsy or seizure severity scores. HDM-LD maps showed accentuated surface changes over the lateral hippocampal surface, in the region of the Sommer sector, in the hippocampi affected by HS. However, HS−ve hippocampi showed maximal surface changes in a different pattern, and did not involve the region of Sommer sector. Conclusion: We conclude that differences in segmental volume loss between the HS−ve and HS+ve groups are suggestive that the underlying pathophysiology of hippocampal changes in the two groups is different, and not related to chronic seizure duration or severity.

Perfusion patterns in postictal 99mTc-HMPAO SPECT after coregistration with MRI in patients with mesial temporal lobe epilepsy

OBJECTIVES To assess patterns of postictal cerebral blood flow in the mesial temporal lobe by coregistration of postictal 99mTc-HMPAO SPECT with MRI in patients with confirmed mesial temporal lobe epilepsy. METHODS Ten postictal and interictal99mTc-HMPAO SPECT scans were coregistered with MRI in 10 patients with confirmed mesial temporal lobe epilepsy. Volumetric tracings of the hippocampus and amygdala from the MRI were superimposed on the postictal and interictal SPECT. Asymmetries in hippocampal and amygdala SPECT signal were then calculated using the equation: % Asymmetry =100 × (right − left) / (right + left)/2. RESULTS In the postictal studies, quantitative measurements of amygdala SPECT intensities were greatest on the side of seizure onset in all cases, with an average % asymmetry of 11.1, range 5.2-21.9. Hippocampal intensities were greatest on the side of seizure onset in six studies, with an average % asymmetry of 9.6, range 4.7-12.0. In four scans the hippocampal intensities were less on the side of seizure onset, with an average % asymmetry of 10.2, range 5.7-15.5. There was no localising quantitative pattern in interictal studies. CONCLUSIONS Postictal SPECT shows distinctive perfusion patterns when coregistered with MRI, which assist in lateralisation of temporal lobe seizures. Hyperperfusion in the region of the amygdala is more consistently lateralising than hyperperfusion in the region of the hippocampus in postictal studies.

Epilepsy in the nevoid basal-cell carcinoma syndrome (Gorlin syndrome) : Report of a case due to a focal neuronal heterotopia

We present a case of uncontrolled temporal lobe epilepsy due to a focal left temporal neuronal heterotopia associated with the nevoid-basal-cell carcinoma syndrome. This is the first pathologically described lesion associated with temporal lobe epilepsy in this syndrome. Because the patients seizures resolved after a modified left anterior temporal lobectomy, this case illustrates that epilepsy in patients with the nevoid basal-cell carcinoma syndrome is potentially curable and should be investigated appropriately. NEUROLOGY 1996;46: 574-576

Sudden 'stroke-like' onset of hemiparesis due to bacterial brain abscess.

The usual presentation of bacterial cerebral abscess is subacute, evolving over days or weeks, with 80% of all cases presenting within 1 month of the onset of symptoms.’ We report a patient who presented with “stroke-like” onset of hemiparesis and who had a large edematous lesion on CT scanning, reflecting an underlying brain abscess. Case report. A 58-year-old right-handed white man from northern Ohio with a history of hypertension and coronary artery disease presented after sudden onset of a right hemiparesis while fishing. He was fishing in a sitting position when he suddenly could not move his right leg. When he attempted to cast, he also noticed right arm weakness. The weakness did not progress or improve after onset. He was able to walk only with significant assistance. There was no associated sensory symptom, facial droop, dysarthria, dysphagia, headache, nausea, vomiting, vertigo, change in consciousness, or dizziness. He was in his usual state of health until the day of admission. His medications were verapamil sustained-release formulation 240 mg p.0. every morning and 120 mg p.0. every evening, atenolol 50 mg p.0. every day, albuterol inhaler p.r.n., and nitroglycerin 0.4 mg sl p.r.n. chest pain. He smoked one and one-half packs of cigarettes a day and drank approximately six beers a week. He denied any illegal drug use. His medical history included hypertension, diagnosed 3 years prior to admission, mild chronic obstructive pulmonary disease, and severe coronary artery disease, documented by coronary vessel angiogram, with stable angina. On presentation to the hospital, vital signs were temperature 36.3 “C, heart rate 92 beats per minute, respiratory rate 24 breaths per minute, and blood pressure 145183 mm Hg. He was awake, alert, fully oriented, and a good historian. There was no evidence of aphasia. General physical examination was unremarkable, except for mild bilateral diffuse expiratory wheezes. Neurologic examination showed 4+/5 strength of right shoulder shrug with strength of the right extremities as follows: 3/5 deltoid, 5-15 biceps and triceps, 5/5 wrist flexion and extension and grip, 415 hip flexion, 415 knee flexion and extension, and 315 ankle flexion and extension. Deep tendon reflexes were 314 a t the right biceps, knee, and ankle, but were 214 elsewhere. Plantar reflexes were downgoing bilaterally. Routine blood chemistry panel, prothrombin time, and partial prothrombin time were within normal limits. There was a peripheral white blood cell count of 9,200 cells/mm3, with a differential of 65 polymorphonuclear leukocytes, six bands, 20 lymphocytes, th ree eosinophils, and two basophils. ECG showed normal sinus rhythm, with a n old anterior septa1 myocardial infarction, left ventricular hypertrophy, and intraventricular conduction defect. A noncontrasted head CT done 6 hours after the onset of symptoms showed a 3-cm by 4-em left frontal hypodense lesion (figure, A). A follow-up CT with contrast the day after admission showed a ring-enhancing lesion within the left frontal hypodensity, with some enhancement a t the margins of the hypodensity (figure, B). The patient’s condition worsened the day after admission, when he developed seizures. Four days later, he became delirious. His deterioration prompted a left frontoparietal craniotomy, which revealed a bacterial abscess. Cultures grew Streptococcus mi l ler i . Postoperatively he was moving all extremities, but suffered a large myocardial infarction later on the day of surgery, with elevation of creatine phosphokinase to 667 and creatine phosphokinase-MB fraction to 85. He died on postoperative day one. Autopsy was refused. Discussion. This patient had sudden “stroke-like” onset of symptoms. Review of the literature showed prior articles2s3 reporting sudden onset of symptoms in brain abscess cases. However, these cases presented with either headache, transient focal neurologic symptoms, or seizures. To our knowledge, this is the first reported case of a brain abscess to present with a monosymptomatic hemiparesis. The neuroradiologic examination is consistent with a n abscess in the stage of ~ e r e b r i t i s . ~ Kurlan and Griggs3 postulated tha t their sudden-onset cases had ischemic strokes leading to abscess formation, but the CTs of their first two cases were more consistent with abscesses in the cerebritis stage.4 There is precedence for mass lesions presenting with sudden onset of symptoms. Brain tumors, without evidence of hemorrhage, occasionally present with the abrupt development of focal neurologic signs mimicking ~ t r o k e , ~ , ~ as can chronic subdural he ma to ma^.^ Past theories for this phenomenon have included a sudden increase in the amount of edema associated with the lesion, chemical or mechanical stimulation of the cortex causing the spreading cortical depression of Leiio, and mass effect of the lesion causing compromise of cerebral blood flow, leading to i ~ c h e m i a . ~ Since venous thrombosis is a common complication of brain abscess, it could also be responsible for the rapid onset of symptoms. Given the extreme importance of early diagnosis and treatment of bacterial brain abscess, this case reemphasizes the need for prompt neuroimaging with CT or MRI in patients with sudden onset of localizing cerebral symptoms.

Postoperative seizure freedom does not normalize altered connectivity in temporal lobe epilepsy

Specific changes in the functional connectivity of brain networks occur in patients with epilepsy. Yet whether such changes reflect a stable disease effect or one that is a function of active seizure burden remains unclear. Here, we longitudinally assessed the connectivity of canonical cognitive functional networks in patients with intractable temporal lobe epilepsy (TLE), both before and after patients underwent epilepsy surgery and achieved seizure freedom.